First, where do you live or at least what zone are you in? Second, how big is the pot you have it in? Third, are there lots of drainage holes in the bottom of the pot? Fourth, is it inside or outside?

Roses are not house plants. They are never very happy inside because of the reduced light and humidity. In the right size pot (big!), with good drainage, outside they should do very well without having to change the soil or trim the root ball for several years. I have some that have been in the same pot for at least 5 years now.

Find a pot that is at least 15 inches wide and tall. If there is any kind of tray on the bottom take it off. Most pots only have one drainage hole in the bottom center. Drill a few extra holes along the outside edge of the bottom. Any good quality POTTING soil will work. Do not use "garden" or "top" soil ever. It's too heavy and won't drain properly. You do not have to trim the roots unless they are wrapped around in circles tightly. And if you're going up in pot size just tease them loose and re-pot. If you are in a warm zone, 8 or higher, you can just leave it outside all winter and it should to well. If you are in a cold zone you will need to find some kind of winter protection for it. An unheated garage, on a shelf, will work well. Be sure to water it at least once a month all winter long. Even though it looks dead, it's not, and still needs some water.